itch's mistake is the way they handled all of this. But the whole fiasco is payment processors and Collective Shout' fault and they should get most of the blame.
Unfortunately, the all-powerful Steam also caved... That's going to be a tough battle.
Short term solution? Publish games on other platforms that are more friendly towards adult-themed games (easiest, but many of those platforms stinks) or self-host them and sell them yourself (difficult and expensive for most, requires legal advice).